Safety device for cooling systems



March 25, 1952 J. c. SLONNEGER 2,590,135

SAFETY DEVICEFOR COOLING SYSTEMS Filed May 18, 1949 Patented Mar. 25, 1952 2,590,135 SAFETY DEVICE 'iron COOLING SYSTEMS .lohn C: Slornieg'er,l Dallas,` Tex., assigner to The Continental Supply Company, Dallas, Tex., a corporation ofDelaware Application May 1s, 1949, 'serial No; 93,946

This invention relates tofnew and useful improvements in control systems and safety devices for' the. cooling systems' of internal combustion engines.

One' object 'of the invention is to' provide an improved device ofV the character described which will prevent thewater level in thecooling system of an internal combustion engine from exceeding certain desirable maximum and minimum limits.

Still another object of the invention is 'to pro-'- vide an improved control device for4 the cooling systems of internal combustion engines ofthe vapor cooling type having` provision" forr shortlng the ignition system of the engine should the water` level in the cooling s'ystembe'cometoo lO'W.`-

A particular object of theinvention `is to pro'- vide an improved device of the character-Idelscribed' which is effective to shutoff the engine upon a failure of the engine coolant condensing system.

Afstill further object of the' invention is to provide a device of the character described which is simple and compact in structure, is` Well; protected from the' weather, and Which is notf's'ub'- ject to corrosion or other damaging by the engine coolant y A construction designed to carry out the invention will-be hereinafter'described together with other features of the' invention.

The invention will be more readilyundrstood from a reading of the followingvsp'ecication and by reference to the accompanying drawing, wherein an exainplf'e of' the invention is shown, andwhereini Fig 1 iS a schematic view of anint'ernal com-- bu'stonengi'ne, illustrating a control system made in? accordance With this invention, V A l Fig. 2 isa view in' elevation,` partially :broken away; of a control device constructed in accordance with this` invention;A

Figf3 isa vertical' sectional viewofrthe con trolldevice, and' Flete is an enlarged', vertical sectional.` view ofl tliestem' guide kand the diaphragm elemenlt- Reference is made to my copending application SerialNo. 791,485,1iled December 13, 1947; and

entitled Cooling Systems for Internal Combustion Engines, wherein I claim certainr details of thezcoolmgbsystem disclosed but not claimed herein,V i l Inith'eidrawings, the .numeral I0 designates an internal 'fcombustion 'engine carried" upon a support Handhaving a cylinder I2. Sincethe pres 4 claims.` (cl. '12e-41.515)

.arcuate section. 2 I;

ent invention is particularly adaptable foruse with engines of the vapor cooling variety', the usual Waterjacket and reservoir I3 is positioned above the cylinder I2 and surmounted by a radiator i4 having associated therewith a cooling fan I5; .In the normal operation of the engina'the Water jacket and reservoir is occupied by a liquid coolant, such as water, which stands at a level WithinV thefjacket I3' and more or less surrounds the cylinder' I2ior cooling purposes. As the engine is operated' and heats up, the cooling liquid is vaporized and passes upwardly into the radiator ifi and there is condensed by the air being forced through the radiator by the fan I5 so` as to drop by gravity back into the jacket I3. Nor-'- rnally, this entire system includes only a very small air vent so that as a practical result vapors cannot escape and be lost.

If the. height ofthe liquid coolant in the cooling system is too high, there will be foaming and priming of the liquid coolant into the lower portion of the radiator resulting from the boiling of said coolant, which is normal in this type of engine'. The priming results in improper opera# tion ofthe radiator, causes excessive pressure'to he created therein and impairs the condensing function of the radiator. It is therefore extremely important that the liquid level be' kept at or below a determinable maximum height.

It is also-essential, of course, that the liquid level in the cooling system be kept at or above a certain minimum level. It the quantity of coolant in the system is too small, inadequate cooling will result, and the-engine would bede-maged by overheating.

The present invention takes care of both these requirements for a maximum and a minimum level of the cooling liquid by the use of a novel U-tube connection to the cooling system and the `incorporation into said connection of a control device' constructed in accordance with the'teach-4 lngsof this invention. A short pipeor conductor I6 is connected into the Water jacket ofthe engine well below the desired minimum coolant level which has' been designated by the vletter A. The pipe l projects substantially horizon'- tally from the engine and carries upon its outer end a T I'lhaving its lateral branch I8 directed upwardly.v The U-tube proper is connected to the outer branch of the'T I 'I and includes a short .leg It and a long leg 2li. Bothleg's extend vertically andare joined at their lower'ends by an The upper end- 22 of the short legr I9 is bent laterally and connected into the Youter 'branch T Il, while the upper'en'd oi the long leg 2e is open and substantially in horizontal alinement with the desired maximum fluid level which is indicated by the letter B. It is obvious that any time the level of the coolant within the engine rises above the desired maximum represented by the horizontal plane B, the excess of such liquid will overflow the open upper end of the long leg and be thus disposed of. However, because of that portion of the U-tube extending below the pipe I6 and T I1, thermo-Siphonic circulation of the cooling liquid between the engine water jacket and the leg 20 is prevented. With the avoidance of this circulation, there is no opportunity for vapors to escape fromthe cooling jacket through the open upper end of the leg 20 and no loss of the cooling liquid through such escaping vapors is encountered. The U-tube is not important only for its ability to discharge excess portions of the cooling liquids which may be present, but also for preventing the loss of vapors of such cooling liquid through the discharge opening. 1

For guarding against low coolant levels, adiaphragm switch S is connected into the ignition system of the engine and has its diaphragm D exposed through the vertical branch I8 of the T I1 to the -body of coolant. The switch is springloaded and so adjusted as to close when the liquid level in the engine water jacket reaches the minimum level A, thus snorting out the ignition system and stopping the engine. It is found that -this provision also protects against overheating due to breakage of the belt leading to the fan I5. When such breakage occurs, there is no condensing within the radiator I4, or very little condensing, with the result that vapors accumulate in the radiator more rapidly than they can be vented to the atmosphere and pressure builds up in the upper portion of the cooling system. This pressure drives the coolant level downwardly causing the coolant to overow through the leg 20 of the U-tube until the coolant level reaches the inlet through the conductor I6. At this point, vapor begins to escape rapidly through the pipe I6, the T I1, and the U-tube, and the pressure upon the diaphragm D drops, allowing the switch S to close and shut off the engine. Since this cycle of heating and lowering of the coolant level to the conductor I6 takes place very rapidly in the instance of a broken fan belt, the engine is ,allowedto run only a very short time after the coolant level drops below the minimum level A and before thev engine is shut off, whereby no material damage to the engine results.

In Figs. 2, 3 and 4, is illustrated a particularly' .advantageous form of the diaphragm switch .which has :a `number of desirable features. The switch includes a diaphragm housing 23 formed -of a lower dished half 24 and an upper dished half 25, joined together at their margins by suitable bolts 26 so as to form a substantially circular and relatively flat housing. A boss 21 depends centrally of the exterior of the lower housing half 24 and is provided with a screw-threaded opening 21 which receives the upper end of a -suitable nipple 28 which is in turn connected into Athe upper branch I8 of the T I1.

trally of the upper diaphragm housing half 25,

substantially in alinernent with the opening 21 and receives the shank of a screw-threaded stud bolt 3l. An axial bore 32 extends throughout the length of the bolt 3| and has its lower portion enlarged to form a counter bore 33 in the lower half of said bolt and extending to the bottom of the shank thereof. A switch actuating rod 34 extends through the bore 32 and counter bore 33 and projects above and below the stud bolt 3I. The lower end of the rod 34 is screwthreaded and receives a retaining nut 35. A thin circular washer 36 is positioned upon the rod below the nut 35, and the central portion of the diaphragm 29 is clamped between the washer 36 and a circular washer 31 positioned upon the rod between said diaphragm. A second retaining nut 38 holds the washer 31 in snug engage- `ment with the lower surface of the diaphragm.

The diaphragm is free to move downwardly and to move the rod 34 downwardly through the bore 32.` However, upward movement of the diaphragm is limited by the engagement of the upper nut 35 with the lower end of the bolt 3I, whereby the diaphragm is normally substantially unidirectional in movement. A coiled compression spring 39 is disposed within the counter bore 33 and bears against the bottom of said bore and against the upper surface of the nut 35 so as to urge the diaphragm constantly downward toward the bottom half of the diaphragm housing. It is desirable to vary the size and compression strength of this spring in order to regulate the sensitivity of the diaphragm switch and to control the minimum water level within the engine cooling system. As will be explained more fully hereinafter, when the coolant level reaches the desired minimum point, the diaphragm 29 moves downwardly to shut oi the engine, and it is manifest that selection of the size and strength of the spring 39 will determine the level at which the shutting-off operation will take place.

A ring 40, formed of bre or some other material having electrical insulating properties, engages the shank of the bolt 3I and is disposed upon the upper surface of the upper diaphragm housing half 25. A central upstanding neck or collar 4I is provided upon the upper surface of the ring 40 adjacent its bore. An annular housing supporting ring 42 encircles the ring 40 and is provided with an annular internal'flange 43 which rests upon the upper surface of the ring 40 and snugly engages the outer periphery of the upstanding neck 4I. The ring 42 is thus held against downward or against lateral or radial movement. A second insulating ring 44 is also received upon the shank of the bolt 3I and rests upon the upper surface of the flange 43. The head of the bolt 3| in turn rests upon the upper surface of the ring 44, and it is obvious that tightening of the bolt 3l within the bore 30 will clamp the ring 4U between the insulating washers 44 and 40. The ring is thus completely insulated electrically from the body of the diaphragm switch and the diaphragm housing.

An L-shaped contact arm 45 is carried upon the upper end of the rod 34 which is screw-threaded and which projects above the bolt 3|. One end of the arm 45 is provided with an opening 46 through which the rod 34 extends, and suitable securing and adjustment nuts 41 are positioned above and below this arm of the contact member to permit its vertical adjustment. The opposite leg of the contact member extends downwardly at right angles to a point spaced a short distance above the upper surface of the ring 42. It is obvious, that when the diaphragm 29 moves downwardly, the member 45 will engage the ring 42 and establish an electrical circuit therethrough.

`Since engines of this type are almost exclusively operated with a magneto ignition system, it is only necessary to ground the magneto in order to render the ignition system inoperative. For this purpose, a grounding wire 48, which is suitably connected into the magneto (not shown), is connected into the ring 42 by means of a bolt 49 tapped into the margin of said ring. Thus, when the contact member 45 engages the upper surface of the ring 42, the circuit to ground through the wire 48 will be completed through the diaphragm switch structure and the diaphragm housing to the engine frame, and the ignition system will be rendered inoperative thereby stopping the engine. For the purpose of protecting the switch structure, a domed cylindrical housing 50 nts over the periphery of the ring 42 and completely encloses the moving parts of the diaphragm switch. The bolt 49, and other similar bolts which are not shown, may be employed for securing the housing 50 in place.

The general operation of this protection system and of the diaphragm switch have been given hereinbefore. The conductor I6, T I1, and the U- tube pipe function as an overflow when the coolant level in the engine cooling jacket reaches too high a level, but thermo-Siphonic circulation of the coolant to and from the overflow pipe is prevented. The hydrostatic head of the coolant above the under side of the diaphragm 29 is constantly exerted upon said diaphragm and holds the same in its upper position so as to compress the spring 39 and move the contact member 45 out of engagement with the ring 42. So long as this condition continues, the magneto and ignition system of the engine may operate in a normal fashion. However, as soon as the liquid level drops to the minimum point, for any reason which may cause such drop, the hydrostatic head exerted between the diaphragm 29 is no longer sufficient to hold it in its upper position, and it drops to close an electrical circuit through the wire 48, the ring 42, the member 45. and so forth to the frame of the engine, thereby snorting out the magneto, rendering the ignition system of the engine inoperative, and stopping the engine. If the engine begins to overheat because of a failure of the fan belt or of the cooling or condensing portion of the cooling system, vaporization of the coolant will create an internal pressure in the cooling system and force the coolant out through the overflow pipe. When the coolant reaches the level of the inlet to the pipe I6, the vapor will flow through said pipe and there will no longer be a hydrostatic head exerted upon the under side of the diaphragm 29. At this point, the diaphragm drops and the engine is stopped. It is further to be noted that regulation and control of the minimum coolant level may be eiected through adjustment of contact member 45 upon the upper end of the rod 34. By raising and lowering the contact member upon the rod, a closing of the electrical circuit may be eiTected at different hydrostatic heads which are exerted upon the diaphragm 29, and thus varying minimum levels within the engine cooling system may .be obtained. It is obvious that the higher the contact member 45 is adjusted with respect to the rod 34, the lower will be the pressure or hydrostatic head at which the diaphragm Will function to close the electrical circuit, short out the magneto and stop the engine.

It is further to be noted that the device and the system is not limited in its use to horizontal engines, but that they may be applied to vertical engines, multicylinder engines, and with apparent modiiication to engines employing ignition systems rather than the magneto type. It is only necessary that the open upper end of the long leg 20 of the U-tube be positioned at the desired maximum coolant level and that the normal minimum level be at least slightly above the diaphragm 29 so as to permit the use of the spring 39. Further, the emergency minimum level, which is reached when the condensing portion of the cooling system fails, must be not higher than the point of connection of the U-tube into the cooling jacket.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A control system for internal combustion engines having coolant jackets, including, an open-ended conductor having one end connected into the coolant jacket and its opposite end open and disposed in a horizontal plane above the point of connection of the conductor into the coolant jacket, a pressure-responsive member in direct communication with the conductor, said member being below the open upper end of the conductor, and means adapted to be actuated by the pressure-responsive member for rendering the engine inoperative.

2. A control system as set forth in claim 1, wherein the conductor communicates with the engine coolant jacket at the normal minimum coolant level therein, and the open upper end of the conductor is disposed in the horizontal plane of the normal maximum coolant level in said jacket.

3. A control system as set forth in claim 1, wherein the conductor is U-shaped.

4. A control system as set forth in claim 1, wherein the pressure-responsive member is disposed closely adjacent the engine coolant jacket.

JOHN C. SLONNEGER.

REFERENCES CITED The following references are of record in the 111e of this patent:

UNITED STATES PATENTS Number Name Date 1,147,232 Gibson July 20, 1915 1,432,518 Armstrong Oct. 17, 1922 1,607,151 Diamant Nov. 16, 1926 1,932,704 McQuiston Oct. 31. 1933 2,191,216 Mendez Feb. 20, 1940 2,327,558 Reavis Aug. 24, 1943 

